Fuel flow

[Doc]

Problem or coincidence with an unknown?  '54 Early Special almost vapor locked near the end of a 40-mile drive a few weeks ago. Not driven real often. So I installed an electric pump for priming and in case of vapor lock. This is a different electric fuel pump than I have on the other cars; it runs very quietly and is good either -/+ ground. However after I installed the pump, the car died on me within a 1/4 mile twice and was hard starting even though two good streams in the carb. and fuel in the transparent filter. But I noticed the inlet/outlet to the pump are 1/4" while the lines are 5/16" by design. Anyone experience a problem with a 1/4" openings pump? I did not have the pump activated at any time.  I'm thinking the pump may be restricting the fuel flow. I noticed when I pulled it off the car, it took a good bit of time to drain out.

[kenneth]

Hi did You have a filter installed between the fueltank and the pump?If not the pump could have been clogged up and was the pump a free flow or does it have to be running for the fuel to go through it?Then some heat insulation on the fuel line near the engine could be a good idea!

[Doc]

New transparent filter and the spec sheets with the pump indicate it can supplement the mechanical pump.  I have reconfigured the line w/o the electric pump but haven't had a chance yet to drive the car.  But that was the only change I had made.

[54 Kaiser]

Doc:

Important point on the filter with the electric pump is the keyword "before" the pump. The standard location is normally between the mechanical pump and the carb.

Most listings for the new 6 volt electrics is that filter before pump requirement.

One other thing. You may now have significantly more fuel pressure than you did with the mechanical alone. If your carb float and seats are not in really good shape, it might be pushing fuel past them and flooding on you.

[Doc]

Well, I think I have the answer and will confirm on test drive. Old Car Weekly August 13 issue, page 10 states this gear-driven pump must be mounted in parallel with the mechanical pump with a check valve. This newest pump I acquired is that type. I did NOT have the wires hooked up yet to test that on the car as every electric pump I have ever used in the past (a couple dozen or so) would pump right through the electric pump.  This article states the pump must be on.  So, that pump will not suffice for priming and occasional vapor lock in the standard configuration mounting.  Have not heard of this before, but this was the first type pump like this I have acquired.

[Doc]

Test drive has confirmed.

[Doc]

Additional longer drive today w/o gear-driven electric pump on the car and I didn't get stranded, so it would seem very conclusive that type pump restricts fuel flow via the standard mechanical pump when in series as is normallly the case.